public class Example4_20 {
   public static void main(String args[]) {
     char a[] = {'a','b','c','D','E','F'};
     for(int i=0;i<a.length;i++) {
       if(Character.isLowerCase(a[i]))
          a[i] = Character.toUpperCase(a[i]);
       else if(Character.isUpperCase(a[i]))
          a[i] = Character.toLowerCase(a[i]);
     }
     for(int i=0;i<a.length;i++)
        System.out.print(" "+a[i]);
   }
}
